Gigabyte rolled out the fifth revision to its 990FXA-UD3 socket AM3+ motherboard, which possibly heralds a series of upgrades to the company's existing socket AM3+ motherboard SKUs. The 990FXA-UD3 Rev. 4 features a host of changes over its UEFI-equipped predecessor, beginning with a refreshed 10-phase CPU VRM (Digital Power Engine), a different selection of chokes, capacitors, and MOSFETs, newer VRM and chipset heatsinks capable of handling higher thermal loads, and Gigabyte's newest UEFI setup program. The board is otherwise identical to the 990FXA-UD3 Rev 3.

Designed with support for AMD FX "Vishera" processors out of the box, the 990FXA-UD3 Rev. 4 features a split power-plane 10-phase CPU VRM, with chokes that don't whine under load, and lower footprint MOSFETs. The CPU socket is wired to four DDR3 DIMM slots supporting up to 64 GB of dual-channel DDR3-2133 MHz memory, and the AMD 990FX northbridge. This chip gives out two PCI-Express 2.0 x16 slots, and two PCI-Express 2.0 x4 slots (physical x16). Two PCI-Express 2.0 x1, and a legacy PCI make for the rest of its expansion. All six SATA 6 Gb/s ports from the SB950 southbridge are assigned as internal ports, while a Marvell 9172 controller handles two eSATA 6 Gb/s. The board offers a total of four USB 3.0 ports, driven by EJ168 controllers by Etron. 8-channel HD audio driven by Realtek ALC889 CODEC, and a gigabit Ethernet interface driven by Realtek 8111F, cover the rest of its connectivity. Since it's a revision to an existing SKU, we expect it to be priced the same, around $140.

It only took Giga two YEARS to listen to me... They insisted they didn't have issues with their VRM circuits with OC'd FX processors but they most definitely did as many enthusiasts were able to prove to Giga who then said it "wasn't a problem" even after they duplicated the overheating VRM circuits.

It only took Giga two YEARS to listen to me... They insisted they didn't have issues with their VRM circuits with OC'd FX processors but they most definitely did as many enthusiasts were able to prove to Giga who then said it "wasn't a problem" even after they duplicated the overheating VRM circuits.

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Are suggesting that anyone with previous revisions shouldn't upgrade to FX CPUs? 'Cause I bought mine (a 990XA-UD3) looking forward to upgrading to those later on...

Are suggesting that anyone with previous revisions shouldn't upgrade to FX CPUs? 'Cause I bought mine (a 990XA-UD3) looking forward to upgrading to those later on...

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No I'm not suggesting that the prior versions of the Giga AM3+ mobos won't run an FX processor. The VRM circuits on these mobos get very hot if you run an 8-core FX-8xxx CPU under heavy load such as non-stop gaming, video editing, stress testing under P95, etc. When the VRM reaches ~90C it starts throttling power to the CPU which causes the CPU to lower it's frequency. As the VRM cools a little it goes back to the set vcore voltage and the CPU ramps up until the VRM gets too hot again and then the CPU slows back down. This cycling continues until the load is reduced and the VRM circuit drops below the thermal threshold.

Gigabyte is finally upgrading their VRM circuit to handle the newer FX-8xxx series CPUs when people OC them.

If you don't ever stress your FX-8xxx CPU as above for lengthy periods of time then you'll never see VRM throttling of the CPU. With a proper VRM circuit and cooling heatsink, you'd never hit the thermal threshold where the VRM starts throttling. VRM overheating is a particular issue for those who OC their CPU. With FX-8xxx CPUs often running at 4.6+ GHz., they can stress the VRM circuit beyond it's intended design - which was for the pre-Bulldozer Phenom CPUs.

This new design provides more headroom for those looking to OC their FX-8xxx CPU and run it hard for long periods of time. It will probably support the FX-9590 also.

If you don't ever stress your FX-8xxx CPU as above for lengthy periods of time then you'll never see VRM throttling of the CPU. With a proper VRM circuit and cooling heatsink, you'd never hit the thermal threshold where the VRM starts throttling. VRM overheating is a particular issue for those who OC their CPU. With FX-8xxx CPUs often running at 4.6+ GHz., they can stress the VRM circuit beyond it's intended design - which was for the pre-Bulldozer Phenom CPUs.

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Thanks for the clarification! I like being able to tweak things, but I never push my hardware too hard anyway. I guess it'll be safe for me to upgrade then.

Finally they went back to heatpipe design vrm+chipset sink, hate that NB sink that wobbles, they use the same sink on the 970 boards too. I have to throw that out and use an old GPU heatsink with fan to cool the 970 NB chipset (that reaches 90C within minutes, now its at 45 to 50C).

Placing a fan on the VRM sink will be much easier than the early puny ones.

Finally they went back to heatpipe design vrm+chipset sink, hate that NB sink that wobbles, they use the same sink on the 970 boards too. I have to throw that out and use an old GPU heatsink with fan to cool the 970 NB chipset (that reaches 90C within minutes, now its at 45 to 50C).

Placing a fan on the VRM sink will be much easier than the early puny ones.

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The HS still looks weak not really 220W for 24/7 ready that's for sure.

8x500GB in RAID-5 on Areca ARC-1220, 4x147GB 15K SAS in RAID-10 on PERC/5i

Optical Drive:

LiteOn 20x DVD+/-RW SATA

LCD/CRT Model:

Viewsonic VP2030b 20.1" 4:3

Case:

Made it myself from aluminum channel and sheet

Sound Card:

ASUS Xonar DX PCIe

Power Supply:

PCPC Silencer 750 Red

Software:

Windows Server 2008 Enterprise x64

Fellow 990FXA-UD3 user here. I've had good results with both an FX-8120 overclocked and an FX-8350 using a Rev 1.0 board. I've not seen thermal throttling, but that may be because of ancillary air movement from the fan I mounted to cool the northbridge.

I made the mistake of touching the northbridge heatsink once before adding a fan and was immediately burned. Interested, I pointed an IR thermometer at the heatsink and discovered that it was running at about 210 degrees (F). No wonder.

The northbridge heatsink is my only real complaint with the board. It has even survived being conformal coated and used for dry ice overclocking sessions.

8x500GB in RAID-5 on Areca ARC-1220, 4x147GB 15K SAS in RAID-10 on PERC/5i

Optical Drive:

LiteOn 20x DVD+/-RW SATA

LCD/CRT Model:

Viewsonic VP2030b 20.1" 4:3

Case:

Made it myself from aluminum channel and sheet

Sound Card:

ASUS Xonar DX PCIe

Power Supply:

PCPC Silencer 750 Red

Software:

Windows Server 2008 Enterprise x64

I'd say Particle style. I coat the boards with polyurethane for that little extra bit of moisture protection (or these days polycrylic since it doesn't yellow like polyurethane does). I was doing this years before ASRock started. It has been a common practice in making rugged electronic circuits for decades, so it isn't like either ASRock or I invented the practice.

I just bought a 9370 for my rev1 ud3 and it wont go past 3.8 ghz in bios even if i set it higher. Funny thing is turbo kicks in sometimes and takes it to 4.7. I also managed to get this thing through software to hit over 5.1ghz and it ran prime95 fine. They just need to release a damn bios update to all there revisions for them. Wish gigabyte would stop with this revision nonsense or provide constant support for their older boards.